They're called "little emperors" - the children born in China under a law that generally limits urban families to having just one child.

They grow up as the sole focus of doting parents. How does this affect them? What does it mean to Chinese society if generations of kids are raised this way?

Concerns about the "only child" practice in China have been expressed before. Now researchers present new evidence that these children are less trusting, less competitive, more pessimistic, less conscientious and more risk-averse than people born before the policy was implemented.

The study's authors say the one-child policy has significant ramifications for Chinese society, leading to less risk-taking in the labor market and possibly fewer entrepreneurs.

"Trust is really important, not just social interactions but in terms of negotiations in business, working with colleagues in business, negotiating between firms," said one of the authors, Lisa Cameron. "If we have lower levels of trust, that could make these kinds of negotiations and interactions more difficult."

China introduced its family planning policy in 1979 to curb a growing population. It limits most urban couples to one child.

The work by Cameron, of Monash University in Australia, and co-authors is published online Friday in the journal Science. The researchers said the results don't necessarily apply to children born outside of the situation they studied: modern-day, urban China.

They administered tests to measure their altruism, trust, trustworthiness, risk attitudes and competitiveness, and gave them personality surveys. Cameron said the participants' ages and views on ideological changes in China didn't appear to affect the results.

"Only children in Chinese families are loved and given almost everything by their families, and they can get resources at home without competition," she said. "Once they enter society, they are no different from other people. Having been overly protected, they feel a sense of loss and show less competitiveness."

The Chinese government credits the one-child policy with preventing hundreds of millions of births and helping lift countless families out of poverty. But the strict limits have led to forced abortions and sterilizations, even though such measures are illegal. Couples who flout the rules face hefty fines, seizure of their property and loss of their jobs.